1. Field of the Invention
The present invention relates to a laminate-type heat exchanger suitable for use in a car air-conditioner or the like, and more particularly, to the improved structure of the laminate.
2. Description of the Prior Art
Well known heat exchangers used in car air-conditioners include heat exchangers comprising, laminated one on another, a plurality of plates having an excellent heat transfer coefficient. A typical laminate-type heat exchanger is known from the disclosure in, for example, Japanese Examined Utility Model Publication (Kokoku) No. 1-25915, in which the component plates of the laminate are adapted to define, when laminated one on another, a path for each heat exchange medium, that is, adjoining paths through which a high and low-temperature media are passed, respectively, so that a heat exchange takes place between the media because of their difference in temperature.
As described in the above-mentioned Publication, the conventional laminate-type heat exchanger is provided with gaskets of a rubber, soft synthetic resin or the like disposed along the circumferences of the plates and of the medium paths to prevent the heat exchange medium from leaking from between the plates, and engagement recesses are formed for positioning the gaskets in place. The laminate is formed by laminating a plurality of such plates one on another, passing bolts through the plates and tightening the bolts to securely compress the gaskets to each other to ensure the liquid tightness of the gaskets and to rigidly fix the plates to each other.
The above laminate-type heat exchanger structure consists of the plates, gaskets, bolts, etc. Generally, the conventional laminate-type heat exchanger has many parts and thus takes a correspondingly long time and much labor in assembling the parts into a product.
Other types of heat exchangers than the above-mentioned laminate-type heat exchanger structure, such as a fin tube heat exchanger, have a structure of which the parts are assembled by brazing. When assembling the parts of a fin tube heat exchanger, for example, a plurality of heat conductive tubes and a plurality of corrugated fins are alternately held in place and a brazing filler metal is placed between these tubes and fins; then, they are put into a furnace as they are and are heated there so that the brazing filler metal is melted to join the tubes and fins to each other. Namely, this type of heat exchanger can be assembled without any gaskets, bolts and the like as in the laminate-type heat exchanger. This type is also advantageous in that many parts can be joined to each other at the same time, so that this assembling technique using brazing is suitable for mass production purposes. Thus more and more of the recent heat exchangers increasingly employ such a brazed-type structure.
Hence, the component plates should desirably be assembled by brazing also in the laminate-type exchanger. Many recent laminate-type heat exchangers use parts joined by brazing. Taking the junction between the parts into consideration, the laminate-type heat exchanger should desirably be formed by using the brazing technique.